(1) Field of the Invention
The present invention relates to a disk device, particularly to a disk device for consecutively performing a disk conveyance operation for conveying a disk to a replayable position, and a disk installment operation for installing the disk conveyed to the replayable position onto a turntable so as to bring the disk into a replayable clamping state.
(2) Description of Related Art
Conventionally, there have been known devices in which a disk conveyance operation and a disk installment operation are performed by one drive source as this type of disk device. This type of disk device is provided with for example a drive gear driven by a drive source, first transmission means for driving disk conveyance means by the drive gear, and second transmission means for driving disk installment means by the drive gear. The second transmission means is formed by a slide cam member having a rack to be meshed with the drive gear. The disk device is formed so as to move the slide cam member by rotating the drive gear with drive force of the drive source, and switch between a first operation of disk conveyance and a second operation of disk installment by utilizing this movement of the slide cam member.
In the disk device formed as above, in a case where the first operation of the disk conveyance and the second operation of the disk installment are consecutively performed, the drive source is continuously driven, and hence the drive gear is rotated before the drive gear and the rack are meshed with each other. Therefore, at the time of switching the first operation to the second operation, in a case where there is a difference between a speed of moving the slide cam member so as to cause the drive gear and the rack to be meshed with each other and a rotation speed of the drive gear, an excessive load is imposed on those members from an instant when the drive gear and the rack are meshed with each other to the time when the first operation and the second operation are performed at the same time. Thus, there arise problems such as breakage of those members.
For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 9-7268) and Patent Document 2 (Japanese Unexamined Patent Publication No. 2004-348782) disclose methods for prohibiting breakage or the like of buffer means in a case where drive transmission is performed by meshing between a drive gear and a rack.
Patent Document 1 discloses a disk device in which cutouts are provided at both ends of a rack in the longitudinal direction, and at a terminal end of drive transmission, a part of the rack to be meshed with a drive gear can be elastically deformed so as to move away from the drive gear.
Patent Document 2 discloses a disk device in which, when excessive force is applied to a meshing part between a rack and a drive gear, meshing between the rack and the drive gear is released.
Additionally, Patent Document 3 (Japanese Unexamined Patent Publication No. 2008-181603) discloses a method for preventing breakage or the like of a drive gear caused by stopping movement of a rack to be meshed with the drive gear while continuously transmitting drive force of a drive source to the drive gear at the time of finishing an ejecting operation of a disk tray.
Patent Document 3 also discloses a disk device in which a sub-rack is slidably provided at an end on the downstream side in the moving direction of a rack, and a drive gear is meshed only with the sub-rack at the same time as stoppage of ejection of a disk tray. In the disk device of Patent Document 3, by meshing the drive gear with the sub-rack at the same time as the stoppage of the ejection of the disk tray, rotation force of the drive gear is not transmitted to the stopped rack but transmitted only to the sub-rack. Thus, even when stoppage of the drive gear is delayed, a load imposed on the drive gear is reduced by sliding of the sub-rack.
However, in the disk device of Patent Document 1, as the buffer means in a case where the drive transmission is performed by the meshing between the drive gear and the rack, an end of the rack itself is elastically deformable. Accordingly, the drive gear and the rack are not continuously meshed with each other, and thus not applicable as the buffer means in a case where the second operation is consecutively performed after the first operation. In the disk device of Patent Document 2, the meshing itself between the rack and the drive gear can be released. Thus, in a case where excessive force is applied, the meshing between the rack and the drive gear is sometimes released during the disk conveyance operation and the disk installment operation. Therefore, in the disk device of Patent Document 2, the second operation cannot be performed consecutively after the first operation. Accordingly, in such devices of Patent Document 1 and Patent Document 2, buffering is not performed at the time of switching from the first operation to the second operation. Thus, the problems such as occurrence of the breakage of the drive gear or the rack cannot be solved.
In the disk device of Patent Document 3, the sub-rack is formed to absorb and reduce impact force. However, the sub-rack rotates a pinion until a drive motor is stopped at the time of the stoppage of the ejection of the disk tray. Therefore, the breakage or the like of the drive gear and the rack at the time of finishing the ejecting operation of the disk tray can be prevented but the sub-rack is not applicable as drive transmission means at the time of switching transmission when the disk conveyance operation and the disk installment operation are consecutively performed. That is, in the disk device of Patent Document 3, the drive gear is meshed only with the sub-rack at the same time as the stoppage of the ejection of the disk tray at the end of drive of the rack by the drive gear. The buffer means by this sub-rack is operated at the time of stoppage of the drive transmission, and the drive gear is only stopped by stoppage of the drive force of the drive source after the buffering operation. In order to consecutively perform the first operation of the disk conveyance and the second operation of the disk installment by one drive source, there is a need for continuously driving the drive gear without stopping the drive force of the drive source at the time of switching the operations, and moving the slide cam member. Since the disk device of Japanese Unexamined Patent Publication No. 2008-181603 does not continuously drive the drive gear at the time of switching, the disk device is not applicable as it is. Accordingly, even with the disk device of Patent Document 3, the problems such as occurrence of the breakage of the drive gear or the rack cannot be solved.